As a plasma processing apparatus such as a dry etching apparatus and a CVD apparatus, what is known is an apparatus that includes: a plasma processing unit in which plasma processing to substrates is performed; a substrate stock unit; a conveying unit that stores a conveying apparatus for conveying substrates between the plasma processing unit and the stock unit. In addition to these unit, the apparatus further includes, as a chamber separate from the aforementioned units, an alignment unit in which alignment of the substrates is performed before the substrates are fed into the plasma processing unit (see Patent Documents 1 to 4).